xfire question

ok I just made a 180 degrees move, skrew the micro atx, I went to an Antec 900, just ordered thid mb http://www.newegg.com/Product/Product.aspx?Item=N82E16813130136
I already have a diamond viper 3870 vid card, my question is, I want to go xfire, do I have to order the same card or any other 3870 will do the trick? I also have a phenom 9600be, canI consider my rig as a spider platform? Thx in advance and pardon my ignorance!

If it were me? I would get the same, not to complicate things.

It will work but with a different brand name card, it's the chip-sets that should be the same though with CrossfireX that's not supposed to be a problem any longer. As for the Spider Platform and looking at your board of choice and if you were to run 4 video card on it it would be considered a Spider platform.